Vision assessment today is most commonly carried out either with basic screening charts or by professional evaluation by a trained optometrist or ophthalmologist. Many well known screening tests are available. The well-known Snellen acuity chart is widely used, but other charts such as the “tumbling E” chart, the “Landolt C” chart, and the Amsler grid chart are also commonly used. Use of vision charts is suitable for analysis of common vision problems such as focusing disorders, but they are of limited value for monitoring more serious disorders such as diabetic retinopathy, age-related macular degeneration, and other serious disorders. These diseases have the potential to become active and degenerate rapidly. If not properly treated, permanent vision loss or even blindness may occur.
Of course, methods exist for diagnosing and treating these more serious conditions. However, they generally require expensive and sophisticated equipment that must be operated by a specially trained technician, such as an optometrist or an ophthalmologist. In fact, the only commonly available tool for self-monitoring of most retinal disorders is the paper Amsler grid test. The Amsler grid is simply a square grid ruled on paper or cardboard. The user tests each eye individually by fixating on the grid and noting any grid segments that appear to be missing, wavy, or distorted. While simple and low cost, the Amsler grid is difficult to use since the individual must subjectively assess their own condition, it is not quantitative, and it can be very hard for patients to determine if missing, wavy, or distorted grid segments are slightly more or less pronounced from one test to the next.
Hence, a low cost vision screening and assessment system that can detect the early signs of vision disorders, track their progress, and/or assess their relative severity is highly valuable. Such a system would allow persons to test their vision for serious vision disorders such as macular degeneration, diabetic retinopathy, glaucoma, and other disorders. Persons suffering from such disorders could use such a system to track their condition and validate the effects of their treatment in an objective and quantitative manner. And, of course, objective and quantitative vision testing can also be very useful to care providers in optimizing treatments for their patients.